Lindy's Chocolate Fudge Cake Problems.

I had a go at making lindy's chocolate fudge cake http://www.lindyscakes.co.uk/2011/02/02/lindys-chocolate-fudge-cake-recipe/. I didn't want to waste ingredients so scaled down the recipe to a quarter and made it in a little loaf tin. It rose well and tastes OK, but it seemed very light and airy. I expected it to be more dense. I can compress it very easily so I don't see how it will stand up to covering with fondant. Could this be due to the scaling down? It needed an eighth of a teaspoon of bicarbonate of soda (baking soda). I don't have a spoon that small so possibly over estimated.

Also it's not really fudgy and it's very sweet. I used caster sugar. Would light brown muscovado be better? I use that in brownies and they are very fudgy. And can I reduce the sugar in this type of recipe or will it fail?

ACan't help with the scaling down but I made that cake for the first time the other day. It looked, tasted and behaved like her chocolate mud cake to me, not very fudgey. I used caster sugar too so it might be that.

When I started making mud cakes I used the recipe from lindys website. She says it's planet cakes recipe, adapted slightly for uk ingredients/measurements. It's easy to make and so delicious but it doesn't behave very well for me. The top cracks, it's really hard to cut and often breaks apart when I try to. Somebody started a thread cos they were having the same problems, I gave it a bump but no one replied. Such a shame cos it really is such a yummy cake. I tried the fudge cake recipe last week, it smelled like a mud cake, cracked like a mud cake (though not quite as badly), behaved like a mud cake and tasted like a mud cake. Delicious but not very fudgey. I did manage to cut it a little easier but it was still threatening to break apart at any time.

Regarding holding up well under fondant, I've covered most of my mud cakes with fondant and they were fine, one was in pieces, I was literally piecing the bits of cake back on, gluing it together with ganache and squishing it back into shape with my hands! I was a bit worried but they were fine, fondant went on, they travelled well and held their shape when they were cut.
The fudge cake I didn't cover with fondant, just ganached it and stuck cigarello's all around it. It was dowelled to death and had a tier on top, travelled for over an hour in a hot car and was absolutely fine.
I might try with brown sugar next time, see if it makes it fudgier.